Improvement following total knee replacement surgery: Exploring preoperative symptoms and change in preoperative symptoms

The STAR care pathway for patients with chronic pain after total knee replacement: four-year follow-up of a randomised controlled trial

BACKGROUND

The Support and Treatment After Replacement (STAR) care pathway is a clinically important and cost-effective intervention found to improve pain outcomes over one year for people with chronic pain three months after total knee replacement (TKR). We followed up STAR trial participants to evaluate the longer-term clinical- and cost-effectiveness of this care pathway.

METHODS

Participants who remained enrolled on the trial at one year were contacted by post at a median of four years after randomisation and invited to complete a questionnaire comprising the same outcomes collected during the trial. We captured pain (co-primary outcome using the Brief Pain Inventory (BPI) pain severity and interference scales; scored 0-10, best to worst), function, neuropathic characteristics, emotional aspects of pain, health-related quality of life, and satisfaction. Electronic hospital informatics data on hospital resource use for the period of one to four years post-randomisation were collected from participating hospital sites. The economic evaluation took an National Health Service (NHS) secondary care perspective, with a four-year time horizon.

RESULTS

Overall, 226/337 (67%) of participants returned completed follow-up questionnaires, yielding adjusted between-group differences in BPI means of -0.42 (95% confidence interval, CI (-1.07, 0.23); p = 0.20) for pain severity and - 0.64 (95% CI -1.41, 0.12); p = 0.10) for pain interference. Analysis using a multiple imputed data set (n = 337) showed an incremental net monetary benefit in favour of the STAR care pathway of £3,525 (95% CI -£990 to £8,039) at a £20,000/QALY willingness-to-pay threshold, leading to a probability that the intervention was cost-effective of 0.94.

CONCLUSIONS

The magnitude of the longer-term benefits of the STAR care pathway are uncertain due to attrition of trial participants; however, there is a suggestion of some degree of sustained clinical benefit at four years. The care pathway remained cost-effective at four years.

TRIAL REGISTRATION

ISRCTN: 92,545,361.

Establishing the Minimal Clinically Important Difference and Patient Acceptable Symptomatic State following Patellofemoral Inlay Arthroplasty for Visual Analog Scale Pain, Western Ontario and McMaster Universities Arthritis Index, and Lysholm Scores

BACKGROUND

The purposes of the study were to define the minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS) after patello-femoral inlay arthroplasty (PFA) and to identify factors predictive for the achievement of clinically important outcomes (CIOs).

METHODS

A total of 99 patients who underwent PFA between 2009 and 2019 and had a minimum of 2-year postoperative follow-up were enrolled in this retrospective monocentric study. Included patients had a mean age of 44 years (range, 21 to 79). The MCID and PASS were calculated using an anchor-based approach for the visual analog scale (VAS) pain, Western Ontario and McMaster Universities Arthritis Index (WOMAC), and Lysholm patient-reported outcome measures. Factors associated with CIO achievement were determined using multivariable logistic regression analyses.

RESULTS

The established MCID thresholds for clinical improvement were -2.46 for the VAS pain score, -8.5 for the WOMAC score, and + 25.4 for the Lysholm score. Postoperative scores corresponding to the PASS were <2.55 for the VAS pain score, <14.6 for the WOMAC score, and >52.5 points for the Lysholm score. Preoperative patellar instability and concomitant medial patello-femoral ligament reconstruction were independent positive predictors of reaching both MCID and PASS. Additionally, inferior baseline scores and age were predictive of achieving MCID, whereas superior baseline scores and body mass index were predictive of achieving PASS.

CONCLUSION

This study determined the thresholds of MCID and PASS for the VAS pain, WOMAC, and Lysholm scores following PFA implantation at 2-year follow-up. The study demonstrated a predictive role of patient age, body mass index, preoperative patient-reported outcome measure scores, preoperative patellar instability, and concomitant medial patello-femoral ligament reconstruction in the achievement of CIOs.

LEVEL OF EVIDENCE

Prognostic Level IV.

Patients Who Have Kellgren-Lawrence Grade 3 and 4 Osteoarthritis Benefit Equally From Total Knee Arthroplasty

BACKGROUND

Recently, some payers have limited access to total knee arthroplasty (TKA) to patients who have Kellgren-Lawrence (KL) grade 4 osteoarthritis only. This study compared the outcomes of patients who have KL grade 3 and 4 osteoarthritis after TKA to determine if this new policy is justified.

METHODS

This was a secondary analysis of a series originally established to collect outcomes for a single, cemented implant design. A total of 152 patients underwent primary, unilateral TKA at two centers from 2014 to 2016. Only patients who had KL grade 3 (n = 69) or 4 (n = 83) osteoarthritis were included. There was no difference in age, sex, American Society of Anesthesiologists score, or preoperative Knee Society Score (KSS) between the groups. Patients who had KL grade 4 disease had a higher body mass index. KSS and Forgotten Joint Score (FJS) were collected preoperatively and at 6 weeks, 6 months, 1 year, and 2 years postoperatively. Generalized linear models were used to compare outcomes.

RESULTS

Controlling for demographics, improvements in KSS were comparable between the groups at all time points. There was no difference in KSS, FJS, and the proportion that achieved the patient acceptable symptom state for FJS at 2 years.

CONCLUSION

Patients who had KL grade 3 and 4 osteoarthritis experienced similar improvement at all time points up to 2 years after primary TKA. There is no justification for payers to deny access to surgical treatment for patients who have KL grade 3 osteoarthritis and have otherwise failed nonoperative treatment.

CT scan analysis of implant mating comparing APA versus TEA in simultaneous bilateral TKA: One technique per knee

BACKGROUND

The optimal landmark for setting femoral component rotation in primary TKA remains a debate. This study compares the Anterior-Posterior Axis (APA) versus the Transepicondylar Axis (TEA) in patients undergoing simultaneous bilateral TKA, where one reference line was randomized to each knee. Implant mating was assessed via post-operative CT scans.

METHOD

The study included 32 patients with osteoarthritis in both knees with similar varus deformities. All patients underwent the same surgical procedure on both knees, aside from the selected femoral rotation axis line: APA randomized to one side and TEA to the contralateral. Post-operative CT scans were performed in extension to assess in-vivo mating.

RESULTS

CT scan analysis showed mean rotation of the femoral implant externally rotated relative to the radiographic TEA with no significant difference between the APA and TEA groups (p = 0.28). Tibial implant rotation was also externally rotated to the radiographic TEA with no significant difference (p = 0.59). Femoral-tibial implant mating showed a mean external rotation of the tibia relative to the femur in both groups: 0.86 ± 4.0° external rotation in the APA group and 0.23 ± 3.7° external rotation in the TEA group. There was no significant difference between groups (p = 0.52). The range of mating mismatch was 15° in the APA group and 16.5° in the TEA group.

CONCLUSIONS

When using a measured resection, posterior referencing technique, post-operative femoral-tibial implant mating measured by CT scan showed no superiority comparing the APA method versus the TEA method.

LEVEL OF EVIDENCE

2 Randomized prospective study.

Promoting physical activity via physical therapist following knee replacement: A pilot randomized controlled trial

BACKGROUND

Outpatient physical therapy may be an opportune time to promote aerobic physical activity after knee replacement; however, it is unknown if it is feasible to integrate a physical activity intervention within standard physical therapy.

OBJECTIVE

To examine the feasibility and acceptability of a physical activity intervention delivered within outpatient physical therapy for adults after knee replacement.

METHODS

As part of a cluster randomized trial, adults with knee replacement starting outpatient physical therapy were recruited across four physical therapy sites. Sites were randomized and physical therapists delivered either an enhanced physical activity intervention or a control condition. The enhanced physical activity intervention consisted of standard postoperative physical therapy plus goal setting, problem-solving, and use of motivational interviewing techniques to promote 150 minutes/week of aerobic moderate intensity physical activity. The control group received standard postoperative physical therapy only. Feasibility and acceptability were determined based on recruitment and retention rates at 12 weeks after surgery. Outcomes including objectively measured physical activity, pain, and self-reported function were examined at the baseline postoperative visit and 12 weeks later.

RESULTS

Thirty-three percent of candidates screened were randomized (n = 45) and retention at 12 weeks after surgery was 91% (no difference by condition). Moderate-intensity activity increased, pain decreased, and self-reported function improved, but there were no statistically significant group differences between baseline and 12 weeks.

CONCLUSION

Implementing a physical activity intervention within outpatient physical therapy for adults after knee replacement is feasible; however, in this pilot study, changes were not observed in moderate intensity physical activity as compared to standard postoperative physical therapy. Future studies are needed to explore additional low-cost strategies and the optimal time to promote physical activity after knee replacement.

There are Considerable Inconsistencies Among Minimum Clinically Important Differences in TKA: A Systematic Review

BACKGROUND

Patient-reported outcome measures (PROMs) are frequently used to assess the impact of total knee arthroplasty (TKA) on patients. However, mere statistical comparison of PROMs is not sufficient to assess the value of TKA to the patient, especially given the risk profile of arthroplasty. Evaluation of treatment effect sizes is important to support the use of an intervention; this is often quantified with the minimum clinically important difference (MCID). MCIDs are unique to specific PROMs, as they vary by calculation methodology and study population. Therefore, a systematic review of calculated MCID values, their respective ranges, and assessment of their applications is important to guide and encourage their use as a critical measure of effect size in TKA outcomes research.

QUESTIONS/PURPOSES

In this systematic review of MCID calculations and reporting in primary TKA, we asked: (1) What are the most frequently reported PROM MCIDs and their reported ranges in TKA? (2) What proportion of studies report distribution- versus anchor-based MCID values? (3) What are the most common methods by which these MCID values are derived for anchor-based values? (4) What are the most common derivation methods for distribution-based values? (5) How do the reported medians and corresponding interquartile ranges (IQR) compare between calculation methods for each PROM?

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review was conducted using the PubMed, EMBASE, and MEDLINE databases from inception through March 2022 for TKA articles reporting an MCID value for any PROMs. Two independent reviewers screened articles for eligibility, including any article that calculated new MCID values for PROMs after primary TKA, and extracted these data for analysis. Overall, 576 articles were identified, 38 of which were included in the final analysis. These studies had a total of 710,128 patients with a median age of 67.7 years and median BMI of 30.9 kg/m 2 . Women made up more than 50% of patients in most studies, and the median follow-up period was 17 months (range 0.25 to 72 months). The overall risk of bias was assessed as moderate using the Jadad criteria for one randomized controlled trial (3 of 5 ideal global score) and the modified Methodological Index for Non-randomized Studies criteria for comparative studies (mean 17.2 ± 1.8) and noncomparative studies (mean 9.6 ± 1.3). There were 49 unique PROMs for which 233 MCIDs were reported. Calculated values were classified as anchor-based, distribution-based, or not reported. MCID values for each PROM, MCID calculation method, number of patients, and study demographics were extracted from each study. Anchor-based and distribution-based MCIDs were compared for each unique PROM using a Wilcoxon rank sum test given non-normal distribution of values.

RESULTS

The WOMAC Function and Pain subscores were the most frequently reported MCID value, comprising 9% (22 of 233) and 9% (22 of 233), respectively. The composite Oxford Knee Score (OKS) was the next most frequently reported (9% [21 of 233]), followed by the WOMAC composite score (6% [13 of 233]). The median anchor-based values for WOMAC Function and Pain subscores were 23 (IQR 16 to 33) and 25 (IQR 14 to 31), while the median distribution-based values were 11 (IQR 10.8 to 11) and 22 (IQR 17 to 23), respectively. The median anchor-based MCID value for the OKS was 6 (IQR 4 to 7), while the distribution-based value was 7 (IQR 5 to 10). Thirty-nine percent (15 of 38) used an anchor-based method to calculate a new MCID, while 32% (12 of 38) used a distribution-based technique. Twenty-nine percent of studies (11 of 38) calculated MCID values using both methods. For studies reporting an anchor-based calculation method, a question assessing patient satisfaction, pain relief, or quality of life along a five-point Likert scale was the most commonly used anchor (40% [16 of 40]), followed by a receiver operating characteristic curve estimation (25% [10 of 40]). For studies using distribution-based calculations, all articles used a measure of study population variance in their derivation of the MCID, with the most common method reported as one-half the standard deviation of the difference between preoperative and postoperative PROM scores (45% [14 of 31]). Most reported median MCID values (15 of 19) did not differ by calculation method for each unique PROM (p > 0.05) apart from the WOMAC Function component score and the Knee Injury and Osteoarthritis Outcome Score Pain and Activities of Daily Living subscores.

CONCLUSION

Despite variability of MCIDs for each PROM, there is consistency in the methodology by which MCID values have been derived in published studies. Additionally, there is a consensus about MCID values regardless of calculation method across most of the PROMs we evaluated.

CLINICAL RELEVANCE

Given their importance to treatment selection and patient safety, authors and journals should report MCID values with greater consistency. We recommend using a 7-point increase as the MCID for the OKS, consistent with the median reported anchor-based value derived from several high-quality studies with large patient groups that used anchor-based approaches for MCID calculation, which we believe are most appropriate for most applications in clinical research. Likewise, we recommend using a 10-point to 15-point increase for the MCID of composite WOMAC, as the median value was 12 (IQR 10 to 17) with no difference between calculation methods. We recommend use of median reported values for WOMAC function and pain subscores: 21 (IQR 15 to 33) and 23 (IQR 13 to 29), respectively.

Less improvement in knee function and higher rates of dissatisfaction in the short-term following total knee arthroplasty in people with mild radiographic arthritis

INTRODUCTION

The purpose of this study was to assess if severity of radiographic changes of knee arthritis was associated with patient improvement after total knee arthroplasty (TKA). We hypothesised that patients with mild arthritis were more likely to report lower satisfaction, improvement in knee function and Oxford knee score (OKS) compared to patients with moderate or severe arthritis.

MATERIALS AND METHODS

Secondary analysis of prospectively collected data from TKA patients of two arthroplasty centres with knee radiographs available for assessment of disease severity. Patients completed the Oxford knee score (OKS) and were asked to rate the global improvement in knee condition and their satisfaction at 6 months post-TKA. Bivariable analysis and multivariable regression models were used to test the association between disease severity and each outcome.

RESULTS

2226 patients underwent primary TKA and 3.6% had mild arthritis. Mean OKS improved from 17.0 (SD 18.0) to 38.0 (SD 8.1) 6 months after TKA. Two hundred and twenty-two patients (10%) reported 'Poor' or 'Fair' satisfaction, and 173 (8%) reported knee function was 'Much worse', 'A little worse' or 'About the same' 6 months post-TKA. Patients with mild arthritis showed improvement in OKS [mean improvement in OKS = 19 (SD 15)], but were significantly more likely to report dissatisfaction (OR = 3.10, 95% CI 1.62 to 5.91, p = 0.006), lack of improvement (OR = 4.49, 95% CI 2.38 to 8.47, p < 0.001) and lower OKS scores (- 3 points, 95% CI - 5.39 to - 0.85, p = 0.008) compared to patients with moderate to severe arthritis.

CONCLUSIONS

While patients with mild radiographic arthritic changes improve after TKA, they were significantly more likely to report higher rates of dissatisfaction, less improvement in knee function and OKS compared to patients with moderate-severe grades of arthritis.

Progression of chronic pain and associated health-related quality of life and healthcare resource use over 5 years after total knee replacement: evidence from a cohort study

OBJECTIVE

As part of the STAR Programme, a comprehensive study exploring long-term pain after surgery, we investigated how pain and function, health-related quality of life (HRQL), and healthcare resource use evolved over 5 years after total knee replacement (TKR) for those with and without chronic pain 1 year after their primary surgery.

METHODS

We used data from the Clinical Outcomes in Arthroplasty Study prospective cohort study, which followed patients undergoing TKR from two English hospitals for 5 years. Chronic pain was defined using the Oxford Knee Score Pain Subscale (OKS-PS) where participants reporting a score of 14 or lower were classified as having chronic pain 1-year postsurgery. Pain and function were measured with the OKS, HRQL using the EuroQoL-5 Dimension, resource use from yearly questionnaires, and costs estimated from a healthcare system perspective. We analysed the changes in OKS-PS, HRQL and resource use over a 5-year follow-up period. Multiple imputation accounted for missing data.

RESULTS

Chronic pain was reported in 70/552 operated knees (12.7%) 1 year after surgery. The chronic pain group had worse pain, function and HRQL presurgery and postsurgery than the non-chronic pain group. Those without chronic pain markedly improved right after surgery, then plateaued. Those with chronic pain improved slowly but steadily. Participants with chronic pain reported greater healthcare resource use and costs than those without, especially 1 year after surgery, and mostly from hospital readmissions. 64.7% of those in chronic pain recovered during the following 4 years, while 30.9% fluctuated in and out of chronic pain.

CONCLUSION

Although TKR is often highly beneficial, some patients experienced chronic pain postsurgery. Although many fluctuated in their pain levels and most recovered over time, identifying people most likely to have chronic pain and supporting their recovery would benefit patients and healthcare systems.

Mild radiographic osteoarthritis is associated with increased pain and dissatisfaction following total knee arthroplasty when compared with severe osteoarthritis: a systematic review and meta-analysis

PURPOSE

The association between severity of radiographic osteoarthritis with patient pain, function, and satisfaction following total knee arthroplasty has been disputed. The discrepancies in current literature prompt us to further examine this association in a systematic review and meta-analysis.

METHODS

The OVID-Medline, Embase, and Web of Science databases were searched from their inception up to Mar 2020. The main independent variable was osteoarthritis severity as defined by preoperative radiographs. The outcomes measured were pain, function and satisfaction following total knee arthroplasty. A minimum of three studies assessing the same patient-reported outcome measures were included in the meta-analysis, as well as those separating patients by chronic pain or dissatisfaction.

RESULTS

29 studies were included in this study. Significant heterogeneity was seen between radiographic evaluation and reported outcomes. Patients with only mild radiographic osteoarthritis were more likely to suffer from chronic pain (odds ratio = 2.45, 95% CI = 1.80-3.34, p < 0.001) and dissatisfaction (odds ratio = 2.43, 95% CI = 1.79-3.31, p < 0.001) compared to patients with severe osteoarthritis. A significant association was found between mild radiographic severity and lower total Western Ontario and McMaster Universities Osteoarthritis scores (95% CI = - 0.37-0.06, p = 0.006) as well as Knee Society Scores (CI: - 0.54-0.16, p < 0.001).

CONCLUSION

Patients with mild radiographic osteoarthritis are anticipated to gain less from total knee arthroplasty compared to those with severe osteoarthritis. They are also at risk for chronic pain and dissatisfaction and should be consulted about this risk prior to surgery.

LEVEL OF EVIDENCE

III.

Medial unicondylar knee arthroplasty should be reserved for patients with complete joint space collapse

PURPOSE

To determine whether preoperative radiologic joint space width (JSW) is related to the outcome of medial unicondylar knee arthroplasty (UKA) (primary hypothesis).

METHODS

A retrospective comparative analysis was performed. One group was comprised of UKA patients with preoperative JSW 0-1 mm. Another group was made up of patients with preoperative JSW ≥ 2 mm (range 0-4 mm). The JSW was measured from preoperative weight-bearing Schuss-view radiographs. The clinical outcome was determined with the Western Ontario and MacMaster Universities (WOMAC) Osteoarthritis Index score preoperatively and 1 year after medial UKA. Implant survival data were obtained from the arthroplasty register of Tyrol.

RESULTS

There were 80 patients with a preoperative JSW 0-1 mm (age 66, BMI 27.8) and 70 patients with a preoperative JSW ≥ 2 mm (age 64, IQR 15, BMI 28.1). WOMAC total was 10 ± 10 in patients with 0-1 mm JSW and 25 ± 47 in patients with ≥ 2 mm JSW at 1 year postoperative (p = 0.052). WOMAC pain at 1 year postoperative was 7 ± 16 in patients with 0-1 mm JSW and 18 ± 46 in patients with ≥ 2 mm JSW (p = 0.047). WOMAC function at 1 year postoperative was 10 ± 9 in patients with 0-1 mm JSW and 17 ± 51 in patients with ≥ 2 mm JSW (p = 0.048). In patients with 0-1 mm JSW 5 year prosthesis survival was 92.3% and in patients with ≥ 2 mm JSW, it was 81.1% (p = 0.016).

CONCLUSIONS

In patients with preoperative complete joint space collapse (0-1 mm JSW), clinical outcome was superior to that of patients with incomplete joint space collapse. This was true for both 1 year postoperative WOMAC pain and WOMAC function and for 5 year implant survival rates. On the basis of our findings, it is recommended that 'complete joint space collapse' especially be used to achieve best clinical outcome in medial UKA surgery.

LEVEL OF EVIDENCE

IV.

Reducing sedentary time using an innovative mHealth intervention among patients with total knee replacement: Rationale and study protocol

INTRODUCTION

Although knee replacement is effective for improving pain and physical function, subsequent improvements in physical activity typically do not follow. As a result, many patients spend most of their day engaged in sedentary behavior, which may put them at higher risk of experiencing poor function and disability. Intervening on sedentary time, rather than physical activity, may be a more feasible first-step approach for modifying activity-related behaviors in adults who received knee replacement.

OBJECTIVE

The purpose of this study is to examine the use of a mobile health (mHealth) intervention to reduce sedentary time among adults who received a knee replacement at 3 and 6 months after surgery.

METHODS

Patients (n = 92) scheduled for knee replacement will be recruited and at 4 weeks after surgery, they will be randomized to either NEAT!2 or Control. NEAT!2 participants will use the NEAT!2 smartphone app, which provides a vibration and/or audible tone to interrupt prolonged bouts of sitting detected from the smartphone's internal accelerometer, until 3 months after surgery. NEAT!2 participants will receive biweekly coaching calls between 4 and 12 weeks after surgery. Control participants will receive an education control app and receive non-intervention calls to assess general surgery recovery. Both groups will receive 3 retention calls between 3 and 6 months. Data collection will occur pre-operatively and at 3 and 6 months after surgery.

DISCUSSION

The results of this study will help to determine whether an innovative remotely-delivered, mHealth sedentary reduction intervention can decrease sedentary time in adults after knee replacement.

Study of Patients with Bilateral Knee Osteoarthritis Undergoing Total Knee Replacement Procedure with Coexisting Lumbar Spondylosis Symptoms

Study Design

This is a prospective cohort study involving patients who were followed for 2 years after total knee replacement (TKR) to determine changes in lumbar spine and knee symptoms.

Purpose

The objectives of this study were to determine the percentage of patients undergoing bilateral TKR who present with coexisting lumbar spine problems and determine if TKR relieves lumbar spine symptoms.

Overview of Literature

No studies quantify the percentage of TKR patients who experience relief of lumbar spine symptoms after TKR surgery.

Methods

The study included 200 patients (164 females, 36 males) undergoing primary TKR. Follow-up was performed at 4 weeks, 3, 6, 12, and 24 months. Lumbar spine and knee symptom improvements were assessed using the Oswestry Disability Index (ODI) and Oxford Knee Score, respectively.

Results

All 200 patients undergoing bilateral TKR presented with radiographic lumbar spine degenerative pathology; 60% (n=120) of the patients presented with moderate to severe clinical symptoms of lumbar spondylosis, including 54% (n=108) with degenerative lumbar spondylosis and lumbar canal stenosis and 6% (n=12) with degenerative spondylolisthesis. Of the 120 patients who presented with lumbar spine problems, 90% (n=108) reported improvement in their symptoms; the ODI score improved from 42.5%±4.1% preoperative score to 15.6%±2.3% postoperative score (p-value<0.001). Of the 12 patients with no improvement, 10 patients underwent percutaneous procedures for their lumbar spine pathology with good results, one patient underwent surgery, and one declined any intervention.

Conclusions

A significant number of patients (60%) undergoing bilateral TKR also present with symptomatic lumbar spine problems. Patients with mild to moderate lumbar spine degenerative symptoms and no associated severe radiating pain on activity are more likely to experience relief of their symptoms post-TKR.

More Severe Radiographic Osteoarthritis Is Associated With Increased Improvement in Patients' Health State Following a Total Knee Arthroplasty

BACKGROUND

To assess whether preoperative radiological severity of osteoarthritis (OA) is related to the level of improvement in patients' health state measured 1 year after total knee arthroplasty (TKA).

METHODS

Radiographic severity of OA was graded using the Kellgren-Lawrence (KL) classification. Two independent observers were blinded to patients' outcome scores. Health-related quality of life was measured using EQ-5D-3L preoperatively and at 12-month follow-up. The 5 dimensions of the EQ-5D were converted into a health state index score. The association between KL grade and improvement in health state score was analyzed using multiple linear regression.

RESULTS

Among 156 consecutive patients (68% females, mean age 69 years) who underwent primary TKA, 3 knees (2%) were classified as KL grade 2, 115 as KL grade 3 (74%), and 38 as KL grade 4 (24%). Follow-up rate was 77%. There was substantial intra-rater and inter-rater agreement (Cohen's kappa = 0.80 and 0.79). Most patients (64%) had clinically significant improvement in their health state score 1 year after TKA. However, after adjusting for relevant covariates, patients with severe OA (KL grade 4) were found to have significantly more improvement in their health state score than patients with mild or moderate OA (KL grade 2 or 3, respectively). Separate analysis of the 5 EQ-5D dimensions showed that the KL group differences were most evident in the "usual activities" and "pain/discomfort" dimensions.

CONCLUSION

Patients with severe OA have significantly more improvement in their usual activities and pain/discomfort 1 year after TKA than patients with less severe OA.

Widespread Pain Is Associated with Increased Risk of No Clinical Improvement After TKA in Women

BACKGROUND

When conservative treatments do not work, TKA may be the best option for patients with knee osteoarthritis, although a relatively large proportion of individuals do not have clinically important improvement after TKA. Evidence also suggests that women are less likely to benefit from TKA than men, but the reasons are unclear. Widespread pain disproportionately affects women and has been associated with worse outcomes after joint arthroplasty, yet it is unknown if the effect of widespread pain on TKA outcomes differs by patient gender.

QUESTIONS/PURPOSES

(1) Does the association between widespread pain and no clinically important improvement in osteoarthritis-related pain and disability 2 years after TKA differ between men and women? (2) Does the use of pain medications 2 years after TKA differ between those with widespread pain and those without widespread pain before surgery?

METHODS

Osteoarthritis Initiative (https://nda.nih.gov/oai/) study participants were followed annually from March 2005 until October 2015. Participants who underwent TKA up to the 7-year follow-up visit with pain/disability assessment at the protocol-planned visit before TKA and at the second planned annual visit after surgery were included in the analysis. Among 4796 study participants, 391 had a confirmed TKA, including 315 with pain/disability assessment at the protocol-planned visit before TKA. Overall, 95% of participants (298) had the required follow-up assessment; 5% (17) did not have follow-up data. Widespread pain was defined based on the modified American College of Rheumatology criteria. Symptoms were assessed using the WOMAC pain (range 0 to 20; higher score, more pain) and disability (range 0 to 68; higher score, more disability) scores, and the Knee Injury and Osteoarthritis Outcome Score for pain (range 0 to 100; higher score, less pain). Improvements in pain and disability were classified based on improvement from established clinically important differences (decrease in WOMAC pain ≥ 1.5; decrease in WOMAC disability ≥ 6.0; increase in Knee Injury and Osteoarthritis Outcome Score for pain ≥ 9). At baseline, more women presented with widespread pain than men (45% [84 of 184] versus 32% [36 of 114]). Probability and the relative risk (RR) of no clinically important improvement were estimated using a logistic regression analysis in which participants with widespread pain and those without were compared. The analyses were done for men and women separately, then adjusted for depression and baseline outcome scores.

RESULTS

Among women, preoperative widespread pain was associated with an increased risk of no clinically important improvement 2 years after TKA, based on WOMAC pain scores (13.5% versus 4.6%; RR 2.93 [95% CI 1.18 to 7.30]; p = 0.02) and the Knee Injury and Osteoarthritis Outcome Score for pain (16.5% versus 4.9%; RR 3.39 [95% CI 1.34 to 8.59]; p = 0.02). Given the lower and upper limits of the confidence intervals, our data are compatible with a broad range of disparate associations between widespread pain and lack of clinically important improvement in WOMAC pain scores (RR 0.77 [95% CI 0.22 to 2.70]; p = 0.68) and the Knee Injury and Osteoarthritis Outcome Score for pain (RR 1.37 [95% CI 0.47 to 4.00]; p = 0.57) among men, as well as clinically important improvement in WOMAC disability scores among men (RR 0.72 [95% CI 0.20 to 2.55]; p = 0.61) and women (RR 1.98 [95% CI 0.92 to 4.26]; p = 0.08). Participants presenting with widespread pain before TKA were more likely than those without widespread pain to use medication for symptoms of knee osteoarthritis most days for at least 1 month 2 years after TKA (51% [61 of 120] versus 32% [57 of 178]; mean difference, 18.8 [95% CI 7.3 to 30.1]; p < 0.01).

CONCLUSIONS

Widespread pain before TKA was associated with an increased risk of no clinically important improvement in knee pain 2 years postoperatively among women. Because of the small number of men with widespread pain in the sample, the results for men were inconclusive. In clinical practice, screening TKA candidates for widespread pain may be useful, and expectations of surgical outcomes may need to be tempered if patients have a concurrent diagnosis of widespread pain. Future studies should include more men with widespread pain and investigate if treatment of widespread pain before or concurrent with TKA surgery may improve surgical outcomes.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Predicting knee replacement in participants eligible for disease-modifying osteoarthritis drug treatment with structural endpoints

OBJECTIVE

Evaluate associations between 2-year change in radiographic or quantitative magnetic resonance imaging (qMRI) structural measures, and knee replacement (KR), within a subsequent 7-year follow-up period.

METHOD

Participants from the Osteoarthritis Initiative were selected based on potential eligibility criteria for a disease-modifying osteoarthritis (OA) drug trial: Kellgren-Lawrence grade 2 or 3; medial minimum joint space width (mJSW) ≥2.5 mm; knee pain at worst 4-9 in the past 30 days on an 11-point scale, or 0-3 if medication was taken for joint pain; and availability of structural measures over 2 years. Mean 2-year change in structural measures was estimated and compared with two-sample independent t-tests for KR and no KR. Area under the receiver operating characteristic curve (AUC) was estimated using 2-year change in structural measures for prediction of future KR outcomes.

RESULTS

Among 627 participants, 107 knees underwent KR during a median follow-up of 6.7 years after the 2-year imaging period. Knees that received KR during follow-up had a greater mean loss of cartilage thickness in the total femorotibial joint and medial femorotibial compartment on qMRI, as well as decline in medial fixed joint space width on radiographs, compared with knees that did not receive KR. These imaging measures had similar, although modest discrimination for future KR (AUC 0.62, 0.60, and 0.61, respectively).

CONCLUSIONS

2-year changes in qMRI femorotibial cartilage thickness and radiographic JSW measures had similar ability to discriminate future KR in participants with knee OA, suggesting that these measures are comparable biomarkers/surrogate endpoints of structural progression.

Examining Timeliness of Total Knee Replacement Among Patients with Knee Osteoarthritis in the U.S.: Results from the OAI and MOST Longitudinal Cohorts

BACKGROUND

Patients with knee osteoarthritis may undergo total knee replacement too early or may delay or underuse this procedure. We quantified these categories of total knee replacement utilization in 2 cohorts of participants with knee osteoarthritis and investigated factors associated with each category.

METHODS

Data were pooled from 2 multicenter cohort studies that collected demographic, patient-reported, radiographic, clinical examination, and total knee replacement utilization information longitudinally on 8,002 participants who had or were at risk for knee osteoarthritis and were followed for up to 8 years. Validated total knee replacement appropriateness criteria were longitudinally applied to classify participants as either potentially appropriate or likely inappropriate for total knee replacement. Participants were further classified on the basis of total knee replacement utilization into 3 categories: timely (indicating that the patient had total knee replacement within 2 years after the procedure had become potentially appropriate), potentially appropriate but knee not replaced (indicating that the knee had remained unreplaced for >2 years after the procedure had become potentially appropriate), and premature (indicating that the procedure was likely inappropriate but had been performed). Utilization rates were calculated, and factors associated with each category were identified.

RESULTS

Among 8,002 participants, 3,417 knees fulfilled our inclusion and exclusion criteria and were classified into 1 of 3 utilization categories as follows: 290 knees (8% of the total and 9% of the knees for which replacement was potentially appropriate) were classified as "timely", 2,833 knees (83% of the total and 91% of those for which replacement was potentially appropriate) were classified as "potentially appropriate but not replaced", and 294 knees (comprising 9% of the total and 26% of the 1,114 total knee replacements performed) were considered to be "likely inappropriate" yet underwent total knee replacement and were classified as "premature". Of the knees that were potentially appropriate but were not replaced, 1,204 (42.5%) had severe symptoms. Compared with the patients who underwent timely total knee replacement, the likelihood of being classified as potentially appropriate but not undergoing total knee replacement was greater for black participants and the likelihood of having premature total knee replacement was lower among participants with a body mass index of >25 kg/m and those with depression.

CONCLUSIONS

In 2 multicenter cohorts of patients with knee osteoarthritis, we observed substantial numbers of patients who had premature total knee replacement as well as of patients for whom total knee replacement was potentially appropriate but had not been performed >2 years after it had become potentially appropriate. Further understanding of these observations is needed, especially among the latter group.

CLINICAL RELEVANCE

Undergoing total knee replacement too early may result in little or no benefit while exposing the patient to the risks of a major operation, whereas waiting too long may cause limitations in physical activity that in turn increase the risk of additional disability and chronic disease; however, little is known about timing of this surgery. We quantified the extent of premature, timely, and delayed use, and found a high prevalence of both premature and delayed use.

A systematic review of estimates of the minimal clinically important difference and patient acceptable symptom state of the Western Ontario and McMaster Universities Osteoarthritis Index in patients who underwent total hip and total knee replacement

OBJECTIVE

To systematically review the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) estimates in pain and function measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in patients who underwent primary total knee replacement (TKR) and primary total hip replacement (THR).

DESIGN

The study was carried out following PRISMA recommendations. We searched five electronic databases. Two reviewers independently screened titles, abstracts and full-text papers using a priori inclusion/exclusion criteria. Data were extracted by two independent reviewers. Data were synthesized, with WOMAC values converted to 0-100 scores (0 = best, 100 = worst).

RESULTS

Thirteen studies were included. Research methods used to calculate MCIDs and PASS varied across studies (e.g., using anchor-based or distribution methods, wording of anchor questions within anchor-based methods). Baseline WOMAC scores also varied across studies. Across studies and methods, MCIDs for the WOMAC in patients undergoing TKR ranged from 13.3 to 36.0 for pain and 1.8-33.0 for function; values for WOMAC in THR ranged from 8.3 to 41.0 for pain and from 9.7 to 34.0 for function. PASS cut-offs for TKR ranged from 25.0 to 28.6 for pain and 32.3-36.7 for function, and cut-offs for THR from 15.0 to 30.6 for pain and 28.0-42.0 for function.

CONCLUSION

Although the WOMAC is a commonly used measure for a single condition, the variability in methods used to calculate MCID and PASS estimates results in a range of values across studies making it unclear whether values reported in the literature can be applied with confidence. Future research is needed to refine methods used to calculate MCIDs and PASS.

Longitudinal Postoperative Course of Pain and Dysfunction Following Total Knee Arthroplasty

OBJECTIVES

Although the majority of patients undergoing total knee arthroplasty (TKA) report substantial improvement in pain and function, a significant subset experience persistent postsurgical pain and dysfunction. Better understanding of the longitudinal postoperative course is needed, including the association between patient status following physical rehabilitation at 6-weeks post-TKA, to 6-months outcomes. This study aims to described the postoperative course of TKA and examine variables associated with change in pain and functioning between 6-weeks and 6-months post-TKA.

METHODS

In this longitudinal study of 223 participants, assessments of analgesic intake, depression, anxiety, pain catastrophizing, dysfunction, resting and range of motion pain, and pain sensitivity were completed at 6-weeks post-TKA. Analgesic intake, pain ratings, and dysfunction data were also collected at 6-months post-TKA. Pain and dysfunction ratings were divided into none-mild and moderate-severe categories.

RESULTS

Between 6-weeks and 6-months post-TKA, 75% of the sample stayed in the same pain category, 20% improved, and 5% worsened. In terms of functional changes between 6 weeks and 6 months, 65% of the sample stayed in the same functional category, whereas 31% improved and 5% worsened.

DISCUSSION

These findings demonstrate that the majority of patients' pain and functioning remains stable between 6 weeks and 6 months post-TKA. However, a notable subset continues to improve or worsen in pain and functioning and the current study identifies variables associated with these changes.

Predictors of pain severity trajectory in older adults: a 10.7-year follow-up study

OBJECTIVES

To identify distinct pain trajectories over 10.7 years and to examine predictors of identified pain trajectories in an older population and those with radiographic knee osteoarthritis (ROA).

METHODS

963 participants (aged 50-80 years) from a population-based cohort had baseline demographic, psychological, lifestyle and comorbidities data collected. T1-and T2-weighted magnetic resonance imaging (MRI) of the right knee was performed to measure knee structural pathology-cartilage defects, bone marrow lesions (BMLs) and effusion-synovitis. Group-based trajectory modelling (GBTM) was applied to identify trajectories of knee pain over 10.7 years measured by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

Three distinct pain trajectories were defined: 'Minimal pain' (n = 501, 52%), 'Mild pain' (n = 329, 34%) and 'Moderate pain' (n = 165, 14%). In multivariable analysis, having cartilage defects, BMLs and effusion-synovitis were associated with an increased risk of being in the 'Mild pain' (relative risk [RR]: 1.40 to 1.92) and 'Moderate pain' trajectory (RR: 1.72 to 2.26), compared with the 'Minimal pain' trajectory. Being obese and having more painful sites were associated with 'Mild pain' and 'Moderate pain' trajectories, while unemployment, lower education level and presence of emotional problems were associated with 'Moderate pain' trajectory group. Similar results were found for those with ROA.

CONCLUSION

Distinct pain trajectories identified suggest that homogeneous subgroups exist, which might be useful for phenotypic assessment for pain management, particularly in knee osteoarthritis. Structural pathology was associated with worse pain trajectories, suggesting that peripheral stimuli are critical for the development and maintenance of pain severity. Environmental and psychological factors may exacerbate pain perception.

Patient satisfaction after total knee arthroplasty is better in patients with pre-operative complete joint space collapse

Aim of the study

To determine if pre-operative radiologic minimal joint space width (mJSW) is related to the outcome of total knee arthroplasty (TKA) (primary hypothesis). Likewise, the aim was to test if pre-operative mJSW is related to prosthesis survival (secondary hypothesis).

Methods

A retrospective comparative analysis was performed. Group 1 was comprised of patients with pre-operative mJSW 0–1 mm. Group 2 were patients with pre-operative mJSW ≥ 2 mm. The clinical outcome was determined with the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) score pre-operatively and one year after TKA. Only patients with pre-operative weight-bearing radiographs and complete WOMAC score data were accepted.

Results

Available for analysis were 377 patients, of whom 188 were allocated to Group 1 (118 female, 70 male, age 70 ± 11 years) and 189 to Group 2 (118 female, 71 male, age 70 ± 13 years). Pre-operative WOMAC total and WOMAC subscores showed no significant differences between groups. Post-operatively, the WOMAC total was significantly better in Group 1 than in Group 2, 10 ± 22 and 19 ± 31, respectively (p < 0.001, Power 97.5%). Similarly, the WOMAC subscores for pain, stiffness, and function were also significantly better in Group 1 than in Group 2. Five-year prosthesis survival was 94.2 and 91.6% in Groups 1 and 2, respectively (p = 0.07, Power 71%).

Discussion

Patients with pre-operative complete joint space collapse (0 to 1 mm mJSW) achieve a significantly better WOMAC result from TKA than do those with a mJSW equal to or greater than 2 mm. From our findings, it is recommended that “complete joint space collapse” especially be used as an indication for TKA surgery.

Conclusion

Our study was underpowered to sufficiently show an effect of pre-operative mJSW on prosthesis survival.

Electronic supplementary material

The online version of this article (10.1007/s00264-018-4185-3) contains supplementary material, which is available to authorized users.

Early Clinically Relevant Improvement in Quality of Life and Clinical Outcomes 1 Year Postsurgery in Patients with Knee and Hip Joint Arthroplasties

Objective To measure and identify the determinants of the outcomes after hip/knee arthroplasty (HA/KA) in patients with osteoarthritis during the first postsurgical year. Design In this prospective observational study, we evaluated the preoperative and postoperative (3, 6, and 12 months) outcomes of 626 patients who underwent HA (346 with median age 65 years, 59% female) or KA (280 with median age 66.5 years, 54% female) between 2008 and 2013. Generic and specific tools were used to measure health-related quality of life (HRQoL) and utility. Good outcome was defined as an improvement in WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) greater than or equal to the minimal important difference (MID). Regressions were performed to evaluate the relationship between preoperative and postoperative measures and evolution of WOMAC/good outcome. Results We observed an almost systematic improvement of all parameters for up to 12 months, but especially at the 3-month follow-up. The low number of comorbidities and the absence of postoperative complications were the common determinants of improvement of WOMAC total score after 12 months. Other parameters (background of the joint, preoperative function and length of hospital stay in KA group; place of discharge in HA group) affected the evolution of WOMAC scores. 87.09% of HA and 73.06% of KA patients experienced a good outcome. A small number of comorbidities, a worse preoperative function, a shortened hospital stay (KA only), and an absence of early postoperative complications (HA only) significantly predicted a good outcome. Conclusions Intermediate HRQoL following HA or KA improved quickly from preoperative levels for all instruments. More than 70% of patients achieved a good outcome defined as improved pain, stiffness and disability and the predictors are slightly close.

Relationship Between Knee Pain and Patient Preferences for Joint Replacement: Health Care Access Matters

OBJECTIVE

To determine if severity of osteoarthritis-related knee pain is associated with a willingness to undergo total knee replacement (TKR) and whether this association is confounded or modified by components of socioeconomic status and health care coverage.

METHODS

Cross-sectional analysis was conducted among 3,530 Osteoarthritis Initiative study participants. Logistic regression models were used to assess the effect of knee pain severity (where 0 = none, 1-3 = mild, 4-7 = moderate, and 8-10 = severe) on willingness to undergo TKR. Stratified analyses were conducted to evaluate whether socioeconomic status and health care coverage modify the effect of knee pain severity on willingness.

RESULTS

Participants with severe knee pain, compared to participants without pain, were less willing to undergo TKR (odds ratio [OR] 0.73, 95% confidence interval [95% CI] 0.57-0.93). This association was attenuated when adjusted for age, sex, comorbidity, depression, health insurance coverage, prescription medicine coverage, health care source, education, income, employment, race, and marital status (adjusted OR 0.92, 95% CI 0.68-1.24). The odds of willingness to undergo TKR were significantly lower in those with the highest level of pain, compared to those without pain, among participants without health insurance (adjusted OR 0.08, 95% CI 0.01-0.56), but not among those with health insurance (adjusted OR 1.03, 95% CI 0.73-1.38), when adjusted for demographic, clinical, health care access, and socioeconomic factors (P = 0.015). However, <5% of participants were without health insurance.

CONCLUSION

Among participants without health insurance, severe knee pain was paradoxically associated with less willingness to undergo TKR. Policies that improve access to quality health care may affect patient preferences and increase utilization of TKR surgery among vulnerable populations.

Translating Comprehensive Conservative Care for Chronic Knee Pain Into a Digital Care Pathway: 12-Week and 6-Month Outcomes for the Hinge Health Program

Background

Chronic knee pain (CKP) affects a large number of adults, many of whom do not receive best-practice care and are at high risk for unnecessary surgery.

Objective

The aim of this study was to investigate the effect of the Hinge Health 12-week digital care program (DCP) for CKP on knee pain and function, with secondary outcomes of surgery interest and satisfaction, at 12 weeks and 6 months after starting the program.

Methods

Individuals with CKP were recruited onto the 12-week program, comprising sensor-guided physical exercises, weekly education, activity tracking, and psychosocial support such as personal coaching and cognitive behavioral therapy (CBT). We used a single-arm design with assessment of outcomes at baseline, 12 weeks, and 6 months after starting the program. We used a linear mixed effects model with Tukey contrasts to compare timepoints and report intention-to-treat statistics with last observation carried forward.

Results

The cohort consisted of 41 individuals (32 female, mean age 52 years, SD 9 years). Between baseline and week 12, participants reported clinically significant improvements in the Knee Injury and Osteoarthritis Outcome Score (KOOS) pain and Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS) function scales of 16 points (95% CI 12-21, P<.001) and 10 points (95% CI 6-14, P<.001), respectively. Significant reductions of 57% (mean difference 30, 95% CI 21-38, P<.001) and 51% (mean difference 25, 95% CI 16-33, P<.001) in visual analog scale (VAS) knee pain and stiffness, respectively, were observed at 12 weeks, as well as a 67% reduction in surgery interest (mean reduction 2.3 out of 10, 95% CI 1.5-3.1, P<.001). Average satisfaction at week 12 was 9.2 out of 10. Critically, all improvements were maintained at 6 months at similar or greater magnitude.

Conclusions

Participants on the Hinge Health DCP for CKP showed substantial clinical improvements that were maintained 6 months after enrolling in the program. This shows that DCPs carry strong potential to deliver evidence-based, cost-effective care to those suffering from CKP.